The present disclosure relates to a novel dielectric ceramic composition having excellent direct current (DC)-bias characteristics and a multilayer ceramic capacitor containing the same.
In general, electronic components using a ceramic material, such as capacitors, inductors, piezoelectric elements, varistors, thermistors, or the like, include a ceramic body formed of a ceramic material, internal electrodes formed in the ceramic body, and external electrodes mounted on a surface of the ceramic body to be connected to the internal electrodes.
Among ceramic electronic components, a multilayer ceramic capacitor includes a plurality of stacked dielectric layers, internal electrodes disposed to face each other with each of the dielectric layers interposed therebetween, and external electrodes electrically connected to the internal electrodes.
Multilayer ceramic capacitors have been widely used as components for mobile communications devices such as computers, personal data assistants (PDAs), mobile phones, and the like, due to advantages such as compact size, high capacitance, ease of mountablity, and the like.
In general, a multilayer ceramic capacitor is manufactured by stacking a paste for an internal electrode and a paste for a dielectric layer using a sheet method, a printing method, or the like, and simultaneously sintering the stacked pastes.
Recently, with the development of a high capacitance multilayer ceramic capacitor, a thickness of the dielectric layer has been reduced. As a result of the reduction in thickness of the dielectric layer, problems related to reliability, high-temperature withstand voltage characteristics, and short-circuit defects have occurred.
In order to solve these problems, fine barium titanate particles have been used. Furthermore, since it can be difficult to obtain high capacitance, a method has been developed to provide a high capacitance multilayer ceramic capacitor having excellent reliability by using the fine particles but increasing a grain size.
However, in a case of increasing the grain size of barium titanate, permittivity may be increased, but DC-bias characteristics may be deteriorated. That is, when a DC voltage is applied, a capacitance decrease rate may be increased.
As the grain size is increased, the DC-bias characteristics may be further deteriorated. Therefore, in order to solve this problem, a dielectric material capable of implementing high permittivity and having a small grain size may be needed.